Can I combine translucent, SSS and diffuse shaders using the light path node?
The Translucent and Sub Surface Scattering shaders produce only an approximation of what is actually a volumetric effect - of the light scattering throughout the internal volume of the material - and this makes it difficult to combine them realistically. You cannot use the Light Path node for this as there is no Light Path that can distinguish between SSS and Translucent paths (since they are both emulated as surface shaders, not actual volumetric rays).

Instead, use a Volumetric material mixed with the surface Diffuse. This allows the transparency of the surface to be adjusted and also allows the volumetric density and scatter/absorption to be adjusted to get the desired effect.

Here's the material :



Adjust the mix node to vary the surface Diffuse/Transparency. Adjust the Value node to affect the volumetric density. Vary the Diffuse shader to affect the surface color and the RGB node to affect the volume.

This can produce the following effect (note the hair roots showing below the surface) :



(Example produced using Branched Path Tracing inteegrator, increasing the Volume samples (to 6) and similarly increasing the number of Volumetric Bounces in the Light Path properties)